March 19, 2015

Researchers finally locate mysterious vampire crap habitats

With their striking colors and bright yellow eyes, vampire crabs are already popular in the pet trade. However, biologists never really knew where they came from. That is, until a joint team European and Asian team tracked them down.

As report in the Raffles Bulletin of Zoology, vampire crabs come from Southeast Asia and two of the newest and most sought-after species come from separate riverbeds on the Indonesian island of Java.

"These crabs are kind of special because they've been around in the pet trade for ten years, but no one knew where they come from," study author Christian Lukhaup, an aquarist from Waiblingen, Germany, told National Geographic.

One of the new crabs, Geosesarma dennerle has a deep purple color with a cream-colored back. The other new crab, Geosesarma hagen has a bright orange shell and red claws. Both species have the distinctive yellow eyes of all vampire crabs.

Prized pets

The crabs are not entirely new to science, but these two species are – despite having been in the pet trade for some time. The crabs are typically less than one inch wide, making them perfect candidates for small-tank living.

"Dealers working in Southeast Asia and other parts of the world know what their clients are looking for in terms of colors," said study author Christoph Schubart, of Germany's Regensburg University's Institute of Zoology. "They start collecting in areas where scientists may not have made any expeditions so far, and suddenly the market is formed with some animals that no one has ever given a name.”

Lukhaup, who was actually born in Transylvania, said he had to use connections in the somewhat murky pet trade in order to hone in on the natural homes of these two new species.

"There were a lot of false rumors because people don't want other collectors to go there," he said.

The crabs are prized for their distinct colorations and these markings probably evolved as a way for the amphibious crabs to communicate with each other on land, according to Schubart.

"There's much more emphasis on color and visual cues rather than chemical cues, as used in the water,” he said.

There are more hiding elsewhere...probably

Schubart noted that these probably aren’t the last vampire crabs to be discovered on Indonesia's islands. Vampire crabs don't inhabit the ocean, and therefore are essentially confined to a single riverbed or water table.